The adsorption properties of rice husk-based and silicon-freed rice husk-based activated carbon on organic compounds

The activated carbons were prepared from rice husks and silicon-freed rice husks by composite activator. The difference between rice husk-based activated carbon (RAC) and silicon-freed rice husk based activated carbon (FAC) in pore structure and surface chemistry were analyzed. The synthesized activated carbon was used as adsorbents in water treatment. The adsorption properties, isotherms and kinetics of fuchsine on activated carbons were investigated. The results indicated that the BET surface area of RAC and FAC reached 1 924 and 2 433 m2/g, respectively. There FAC has more functional groups compared with RAC. RAC and FAC could improve the removal efficiency of fuchsine at high pH value. The adsorbents could be used in high salt concentration conditions. When the initial pH 7, initial mass concentration 400 mg/L and the adsorbents dosages 0.8 mg/g were used, the adsorption capacity of RAC and FAC was 439 and 483 mg/g, respectively. The Langmuir isotherm model was found to fit well with the adsorption process of RAC and FAC. Both the kinetics and desorption study indicated that the adsorption process was controlled by chemisorption.